Low complexity detector for amplitude phase shift keying‐based differential spatial modulation

Abstract

Differential spatial modulation (DSM) involves the transmission of information through a combination of phase-modulated symbols and transmit antenna index. For efficient use of the wireless system resources, the amplitude information is also utilised as a part of the transmitted data in amplitude-phase shift keying-DSM (APSK-DSM). Here some of the information bits get encoded as differential amplitude in each of the transmit antennas, whenever they are activated resulting in better bandwidth efficiency than conventional DSM. However, prevailing detectors for APSK-DSM have high computational complexity. In this work, the authors proposed a low complexity detector for APSK-based DSM schemes using compressive sensing and an ℓ 2 -norm minimisation for detecting the differential amplitude. To decode this amplitude information, the authors have formulated a column by column decomposition of the received symbol in terms of the amplitude- and phase-modulated symbols received from each transmit antenna. The error performance of the proposed detector is nearly identical to that of existing APSK-based DSM receivers, which use maximum-likelihood detection but with much lower computational complexity than the latter.